U.S. patent application number 12/633938 was filed with the patent office on 2010-08-19 for image recording method, record and image recording system.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Tsuyoshi SANO, Kiyohiko Takemoto, Seishin Yoshida.
Application Number | 20100209677 12/633938 |
Document ID | / |
Family ID | 42474041 |
Filed Date | 2010-08-19 |
United States Patent
Application |
20100209677 |
Kind Code |
A1 |
SANO; Tsuyoshi ; et
al. |
August 19, 2010 |
IMAGE RECORDING METHOD, RECORD AND IMAGE RECORDING SYSTEM
Abstract
[Problems] There is provided an image recording method that
provides resulting images with an excellent gloss and an improved
closeness of contact with the recording medium used. [Solving
Means] An image recording method including a first step for
recording a glossy image layer on a recording medium using a glossy
ink composition containing a metal pigment and a second step for
recording a finishing layer on the glossy image layer using a black
ink composition to reduce the brightness of the glossy image.
Inventors: |
SANO; Tsuyoshi;
(Shiozini-shi, JP) ; Yoshida; Seishin;
(Azumino-shi, JP) ; Takemoto; Kiyohiko;
(Matsumoto-shi, JP) |
Correspondence
Address: |
LADAS & PARRY LLP
26 WEST 61ST STREET
NEW YORK
NY
10023
US
|
Assignee: |
SEIKO EPSON CORPORATION
|
Family ID: |
42474041 |
Appl. No.: |
12/633938 |
Filed: |
December 9, 2009 |
Current U.S.
Class: |
428/195.1 ;
118/300; 427/258; 427/265 |
Current CPC
Class: |
B41J 2/2114 20130101;
B41M 3/008 20130101; B41M 7/009 20130101; C09D 11/322 20130101;
C09D 11/54 20130101; C09D 11/324 20130101; Y10T 428/24802
20150115 |
Class at
Publication: |
428/195.1 ;
427/258; 427/265; 118/300 |
International
Class: |
B32B 3/10 20060101
B32B003/10; B05D 1/36 20060101 B05D001/36; B05D 5/00 20060101
B05D005/00; B05C 5/00 20060101 B05C005/00; B05D 5/06 20060101
B05D005/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 2008 |
JP |
2008-312995 |
Nov 30, 2009 |
JP |
2009-271229 |
Claims
1. An image recording method comprising a first step for recording
a glossy image layer on a recording medium using a glossy ink
composition containing a metal pigment and a second step for
recording a finishing layer on the glossy image layer using a black
ink composition to reduce the brightness of the glossy image.
2. The image recording method according to claim 1, wherein the
concentration of pigment of the black ink composition is equal to
or lower than 1 mass %.
3. The image recording method according to claim 2, wherein the
concentration of pigment of the black ink composition is in the
range of 0.1 to 0.5 mass %.
4. The image recording method according to claim 1, wherein the
black ink composition contains a water-soluble resin.
5. The image recording method according to claim 4, wherein the
concentration of water-soluble resin in the black ink composition
is at least 20-fold greater than the concentration of pigment of
the black ink composition on the solid content basis.
6. The image recording method according to claim 1, wherein the
finishing layer is formed on at least a partial surface of the
glossy image layer.
7. The image recording method according to claim 6, wherein the
finishing layer is formed on the entire surface of the glossy image
layer.
8. The image recording method according to claim 1 performed using
an ink jet recording method.
9. A record obtained using the image recording method according to
claim 1.
10. An image recording system comprising glossy image formation
means for recording a glossy image layer on a recording medium
using a glossy ink composition containing a metal pigment and
finishing layer formation means for recording a finishing layer on
the glossy image layer using a black ink composition to reduce the
brightness of the glossy image.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates to an image recording method
that provides resulting images with an excellent gloss (metallic
luster) and an improved closeness of contact with the recording
medium used, and it also relates to an image provided therewith.
Also, the present invention relates to an image recording system
that provides images with an excellent gloss and an improved
closeness of contact with the recording medium used.
[0003] 2. Related Art
[0004] To produce glossy images on recording media, printing ink
containing gold dust or silver dust made from brass, aluminum fine
particles, and other materials as a pigment, stamping based on the
use of metal foil, thermal transfer based on the use of metal foil,
and other methods have conventionally been used.
[0005] However, when coatings are produced using printing ink
containing gold dust or silver dust, the average particle diameter
of the metal powder used is as large as 10 .mu.m to 30 .mu.m, and
thus matt images can be obtained, but it is difficult to obtain a
mirror luster. Also, when stamping or thermal transfer based on the
use of metal foil is employed, the method used is as follows: an
adhesive agent is applied to a recording medium, a smooth sheet of
metal foil is pressed against the adhesive agent applied, and then
the recording medium and the metal foil sheet are heated while
being kept in contact with each other so that they are fused
together. As a result, a relatively favorable luster is obtained;
however, recording media allowed are limited to ones resistant to
heat and deformation because of the large number of manufacturing
steps and pressure and heat applied during the manufacturing
process. Known techniques for producing glossy images on recording
media are described in, for example, Patent Documents 1 and 2
listed below.
[0006] Recently, the use of ink jet in printing has also often been
seen, and one of examples thereof is metallic printing (for
example, see Patent Documents 3 and 4 listed below).
[0007] However, these known techniques have a problem of low
closeness of contact (adhesiveness) between the resulting glossy
image, which is produced using a glossy ink composition containing
a metal pigment, and the recording medium used, and thus images
produced therewith are inferior in resistance to friction (in other
words, the metal pigments are likely to be peeling). Furthermore,
glossy images produced with the known techniques have insufficient
gloss and thus have room for improvement.
[Prior Publications]
[Patent Documents]
[0008] [Patent Document 1] Japanese Unexamined Patent Application
Publication No. H11-320935
[0009] [Patent Document 2] Japanese Unexamined Patent Application
Publication No. 2006-50347
[0010] [Patent Document 3] Japanese Unexamined Patent Application
Publication No. 2002-179960
[0011] [Patent Document 4] Japanese Unexamined Patent Application
Publication No. 2008-208330
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0012] An object of the present invention is to provide an image
recording method that provides the resulting images with an
excellent gloss and an improved closeness of contact with the
recording medium used.
[0013] Another object of the present invention is to provide an
image recording system that provides images with an excellent gloss
and an improved closeness of contact with the recording medium
used.
Means for Solving the Problems
[0014] The present inventors have conducted extensive research to
solve the above-described problems and found the following: a
glossy image layer is produced using a glossy ink composition
containing a metal pigment (e.g., plate-like aluminum particles),
and then a coating layer (a finishing layer) is produced on this
glossy image layer using a black ink composition that contains
carbon black or some other black pigment at a low proportion so
that the brightness of the glossy image layer be reduced; this
further improves the gloss of the glossy image layer. This is
probably because the surface properties (surface uniformity) of the
glossy image are changed by the black pigment attached to the
glossy image, which has a metallic luster, at a density low enough
to keep the black pigment invisible.
[0015] Additionally, the present invention contains a resin for
fixing the black pigment in the black ink composition, which forms
the coating layer; this allows the lower layer, namely, the glossy
image layer, to have an improved adhesiveness.
[0016] Thus, the present invention is based on the above-described
findings and is as follows.
[0017] (1) An image recording method including a first step for
recording a glossy image layer on a recording medium using a glossy
ink composition containing a metal pigment and a second step for
recording a finishing layer on the glossy image layer using a black
ink composition to reduce the brightness of the glossy image.
[0018] (2) The image recording method according to (1), wherein the
concentration of pigment of the black ink composition is equal to
or lower than 1 mass %.
[0019] (3) The image recording method according to (2), wherein the
concentration of pigment of the black ink composition is in the
range of 0.1 to 0.5 mass.
[0020] (4) The image recording method according to any one of (1)
to (3), wherein the black ink composition contains a water-soluble
resin.
[0021] (5) The image recording method according to (4), wherein the
concentration of the water-soluble resin in the black ink
composition is at least 20-fold greater than the concentration of
pigment of the black ink composition on the solid content
basis.
[0022] (6) The image recording method according to any one of (1)
to (5), wherein the finishing layer is formed on at least a partial
surface of the glossy image layer.
[0023] (7) The image recording method according to (6), wherein the
finishing layer is formed on the entire surface of the glossy image
layer.
[0024] (8) The image recording method according to any one of (1)
to (7) performed using an ink jet recording method.
[0025] (9) A record obtained using the image recording method
according to any one of (1) to (8).
[0026] (10) An image recording system having glossy image formation
means for recording a glossy image layer on a recording medium
using a glossy ink composition containing a metal pigment and
finishing layer formation means for recording a finishing layer on
the glossy image layer using a black ink composition to reduce the
brightness of the glossy image.
ADVANTAGES
[0027] The image recording method according to the present
invention provides the resulting images with an excellent gloss and
an improved closeness of contact with the recording medium
used.
[0028] Recently, there has been an increasing demand for spot
varnish, which is an expression style involving a partial change in
the surface properties of prints or other records. The image
recording method according to the present invention can form a
partial finishing layer, thereby allowing for the easier production
of a glossy image with position-specific gloss.
BEST MODE FOR CARRYING OUT THE INVENTION
Image Recording Method
[0029] The image recording method according to the present
invention includes a first step for recording a glossy image layer
on a recording medium using a glossy ink composition containing a
metal pigment and a second step for recording a finishing layer on
the glossy image layer using a black ink composition to reduce the
brightness of the glossy image.
[0030] First, the glossy ink composition used in the present
invention is described.
[0031] The metal pigment (or metallic pigment) is desirably
plate-like particles and is preferably a metal pigment meeting the
following conditions: the 50% average particle diameter R50 based
on the circle-equivalent diameter calculated from the area of the
X-Y plane of a plate-like particle is in the range of 0.5 to 3
.mu.m, and R50/Z>5, where X, Y, and Z represent the planar
length, planar width, and thickness of the plate-like particle.
[0032] The "plate-like particles" refer to particles having an
almost flat plane (X-Y plane) and an almost uniform thickness (Z).
Such plate-like particles are produced by pulverizing a
metal-deposited film, and thus the metal particles obtained have an
almost flat plane and an almost uniform thickness. Thus, the planar
length, planar width, and thickness of a plate-like particle can be
defined as X, Y, and Z, respectively.
[0033] The "circle-equivalent diameter" is a diameter of a circle
calculated by supposing that the almost flat plane (X-Y plane) of
each plate-like particle contained in the metallic pigment is a
circle having the same projected area as the plate-like particle of
the metallic pigment. For example, when the almost flat plane (X-Y
plane) of each plate-like particle contained in the metallic
pigment is a polygon, the diameter of the circle obtained by
converting the surface of projection of the polygon into a circle
is the circle-equivalent diameter of the plate-like particles
contained in the metallic pigment.
[0034] From the viewpoints of gloss and printing stability, the
above-described 50% average particle diameter R50 based on the
circle-equivalent diameter calculated from the area of the X-Y
plane of a plate-like particle is preferably in the range of 0.5 to
3 .mu.m, more preferably, 0.75 to 2 .mu.m.
[0035] As for the relationship between the above-described 50%
average particle diameter R50 based on the circle-equivalent
diameter and the thickness Z, R50/Z is preferably more than 5 from
the viewpoint of ensuring a high gloss.
[0036] From the viewpoints of cost and ensuring gloss, the
above-described metallic pigment preferably is aluminum or an
aluminum alloy. When an aluminum alloy is used, every kind of
glossy metallic or non-metallic element may be alloyed with
aluminum without particular limitation, and examples thereof
include silver, gold, platinum, nickel, chromium, tin, zinc,
indium, titanium, copper, and so forth. One or more of these
elements, their alloys, and their mixtures can be suitably
used.
[0037] The manufacturing method of this metallic pigment is, for
example, as follows: a composite pigment bulk having a structure
obtained by layering a sheet-like substrate, a resin release layer,
and a metal or alloy layer is separated into two parts at the
interface between the metal or alloy layer and the resin release
layer, and then the metal or alloy layer is pulverized into fine
plate-like particles; then, the plate-like particles obtained are
screened so that ones meeting the following conditions can be
chosen: the 500 average particle diameter R50 based on the
circle-equivalent diameter calculated from the area of the X-Y
plane of a plate-like particle is in the range of 0.5 to 3 .mu.m,
and R50/Z>5, where X, Y, and Z represent the planar length,
planar width, and thickness of the plate-like particle.
[0038] The planar length X, planar width Y, and circle-equivalent
diameter of the above-described metallic pigment (plate-like
particles) can be measured using a particle image analyzer.
Examples of particle image analyzers used include FPIA-2100,
FPIA-3000, and FPIA-3000S flow particle image analyzers
manufactured by Sysmex Corporation.
[0039] The above-described metal or alloy layer is preferably
formed by vacuum evaporation, ion plating, or sputtering.
[0040] This metal or alloy layer is formed with a thickness in the
range of 20 nm to 100 nm, both inclusive. As a result, a pigment
having an average thickness in the range of 20 nm to 100 nm, both
inclusive, is obtained. With an average thickness of not less than
20 nm, the metallic pigment would have higher performances such as
excellent reflectance and gloss. With an average thickness of not
more than 100 nm, the metallic pigment would be guaranteed
dispersion stability with the increase in apparent specific gravity
prevented.
[0041] The resin release layer contained in the above-described
composite pigment bulk is not only an undercoat layer for the
above-described metal or alloy layer but also a release layer that
makes the metal or alloy layer easier to remove from the sheet-like
substrate. Examples of preferred resins for this resin release
layer include polyvinyl alcohol, polyvinyl butyral, polyethylene
glycol, polyacrylic acid, polyacrylamide, cellulose derivatives,
polyvinyl butyral, acrylic-acid-based polymers, and modified nylon
resins.
[0042] The solution of one of the above-listed resins or that of a
mixture of two or more of the resins is applied to a recording
medium, and then the recording medium is dried and subjected to
other treatments, yielding a layer; after being applied, it may be
spiked with additives, such as a viscosity modifier.
[0043] This resin release layer can be applied by any of commonly
used methods including gravure coating, roll coating, blade
coating, extrusion coating, dip coating, spin coating, and so
forth. After being applied and dried, the resin release layer may
be calendered for surface smoothness, if necessary.
[0044] Although not particularly limited, the thickness of the
resin release layer is preferably in the range of 0.5 to 50 .mu.m,
more preferably, 1 to 10 .mu.m. With a thickness of less than 0.5
the resin release layer would fail to meet a quantitative
requirement for serving as dispersion resin. With a thickness of
more than 50 .mu.m, the resin release layer would be likely to be
peeling at the interface with the pigment layer when the composite
pigment bulk is rolled.
[0045] Examples of the sheet-like substrate include, but not
limited to, releasable films such as polyester films made of
polytetrafluoroethylene, polyethylene, polypropylene, polyethylene
terephthalate, or the like, polyamide films made of 6,6-nylon,
6-nylon, or the like, polycarbonate films, triacetate films, and
polyimide films. Ones made of polyethylene terephthalate or its
copolymer are preferable.
[0046] Although not particularly limited, the thickness of this
sheet-like substrate is preferably in the range of 10 to 150 .mu.m.
With a thickness of not less than 10 .mu.m, the sheet-like
substrate would be handled during relevant steps or processes
without any problems. With a thickness of not more than 150 .mu.l,
the sheet-like substrate is highly flexible and thus can be rolled,
removed, or handled in other ways without any problems.
[0047] As described in Japanese Unexamined Patent Application
Publication No. 2005-68250, the above-described metal or alloy
layer may be sandwiched between protective layers. Examples of
protective layers used include silicon oxide layers and protective
resin layers.
[0048] No particular limitation is imposed on the silicon oxide
layers used as long as they are layers containing silicon oxide;
however, they are preferably made by the sol-gel method from a
silicon alkoxide, such as tetraalkoxysilane, or its polymer.
[0049] The silicon oxide layers are formed by applying an alcohol
solution of the silicone alkoxide or its polymer and then heating
and firing the coatings obtained.
[0050] Also on the protective resin layers, no particular
limitation is imposed as long as they are insoluble in the
dispersion medium used. Examples of materials for them include
polyvinyl alcohol, polyethylene glycol, polyacrylic acid,
polyacrylamide, cellulose derivatives, and so forth; preferred ones
include polyvinyl alcohol and cellulose derivatives.
[0051] An aqueous solution of one of the above-listed resins or
that of a mixture of two or more of the resins is applied, thereby
yielding a layer that has been dried and subjected to other
treatments. The application solution may contain additives, such as
a viscosity modifier.
[0052] The above-described silicon oxide or resin is applied by the
same method as that for the resin release layer described
above.
[0053] Although not particularly limited, the thickness of each
protective film is preferably in the range of 50 to 150 nm. With a
thickness of less than 50 nm, the protective films would lack
mechanical strength. With a thickness of more than 150 nm, the
protective films would have excessive strength and thus is
difficult to pulverize or disperse; in some cases, such films are
peeling at the interfaces with the metal or alloy layer.
[0054] In addition, a colorant layer may be disposed between each
protective layer and the metal or alloy layer.
[0055] The colorant layer is introduced to color the composite
pigment. No particular limitation is imposed on the colorant layer
used as long as it contains a pigment that maintains the metallic
pigment glossy and gives any intended hue and tone to the metallic
pigment. The colorant for this colorant layer may be a dye or a
pigment. Any known dye or pigment can be used, if it is
appropriate.
[0056] The "pigment" for this colorant layer is a natural pigment,
a synthetic organic pigment, a synthetic inorganic pigment, or some
other pigment following the usual definition thereof in the field
of pigment chemistry and thus is different from ones having a
layered structure, such as the "composite pigment" used in the
present invention.
[0057] Although not particularly limited, the method for forming
this colorant layer is preferably coating.
[0058] When the colorant contained in the colorant layer is a
pigment, it preferably further contains a colorant dispersion
resin. The colorant dispersion resin preferably has the form of
thin film prepared in the following way: the pigment, the colorant
dispersion resin, necessary additives, and other necessary
ingredients are dispersed or dissolved in a solvent, the solution
obtained is applied by coating to form a uniform liquid film, and
then the liquid film is dried.
[0059] Note that in the production of the above-described composite
pigment bulk, it is preferable in terms of operating efficiency
that the above-described colorant layer and protective layers be
all formed by coating.
[0060] The above-described composite pigment bulk may have a
plurality of the above-described layered structures, each of which
contains the resin release layer and the metal or alloy layer. In
this case, the total thickness of the layered structures organized
by the metal or alloy layers, namely, the thickness excluding those
of the sheet-like substrate and the overlying resin release layer,
in other words, the thickness of the "metal or alloy layer/resin
release layer/metal or alloy layer" or that of the "resin release
layer/metal or alloy layer," is preferably equal to or smaller than
5000 nm. With a thickness of not more than 5000 nm, the composite
pigment bulk would hardly crack or be peeling even when rolled and
thus would be excellent in terms of storage stability.
Additionally, such a composite pigment bulk maintains gloss even
when used as a pigment and thus is favorable.
[0061] In addition, the composite pigment bulk can have a structure
in which the resin release layer and the metal or alloy layer are
layered on the individual faces of the sheet-like substrate.
Anyway, the structure of the composite pigment bulk is never
limited to those described above.
[0062] Although not particularly limited, the method for separating
the composite pigment and the sheet-like substrate is preferably
one in which the above-described composite pigment bulk is immersed
in a liquid or one in which the composite pigment bulk is immersed
in a liquid under ultrasonic treatment for the pulverization of the
composite pigment simultaneous with the removal of the sheet-like
substrate.
[0063] In the pigment obtained in this way, the resin release layer
acts as protective colloid; thus, such a pigment gives a stable
dispersion upon being dispersed in a solvent. Additionally, ink
compositions containing such a pigment can adhere to paper or some
other kind of recording medium thanks to the resin used in this
resin release layer.
[0064] The glossy ink composition used in the present invention
preferably contains the above-described metallic pigment, an
organic solvent, and a resin.
[0065] The concentration of the above-described metallic pigment in
the ink composition is preferably in the range of 0.1 to 10 mass
%.
[0066] When the concentration of the above-described metallic
pigment in the ink composition is not less than 0.1 mass % and less
than 1.5 mass %, ejecting ink at an amount incapable of
sufficiently covering a printing surface would make it possible to
print a texture that has a half-mirror-like glossy surface, or
offers gloss, and, at the same time, has a see-through appearance,
whereas ejecting ink at an amount capable of sufficiently covering
the printing surface would make it possible to produce a metallic
gloss surface that is highly glossy. Thus, such an ink composition
can be suitably used to, for example, produce a half-mirror image
or produce a highly glossy metallic gloss surface on a transparent
recording medium. When the concentration of the metallic pigment in
the ink composition is in the range of 1.5 mass % to 3.0 mass %,
both inclusive, particles in the metal pigment are randomly
arranged on a printing surface, and thus the resulting metallic
gloss surface is not highly glossy, but matt. Thus, such an ink
composition can be suitably used to, for example, coat a
transparent recording medium with a shield layer.
[0067] The above-mentioned organic solvent is preferably a polar
organic solvent. Examples include alcohols (e.g., methyl alcohol,
ethyl alcohol, propyl alcohol, butyl alcohol, isopropyl alcohol,
and fluorinated alcohols), ketones (e.g., acetone, methyl ethyl
ketone, and cyclohexanone), carboxylic acid esters (e.g., methyl
acetate, ethyl acetate, propyl acetate, butyl acetate, methyl
propionate, and ethyl propionate), ethers (e.g., diethyl ether,
dipropyl ether, tetrahydrofuran, and dioxane), and so forth.
[0068] It is particularly preferable that this organic solvent
contain one or more kinds of alkylene glycol ethers that are liquid
at room temperature and pressure.
[0069] Alkylene glycol ethers are mainly composed of any one of
aliphatic groups such as methyl, n-propyl, i-propyl, n-butyl,
i-butyl, hexyl, and 2-ethylhexyl groups, an allyl group, which has
a double bond, and a phenyl group and can be classified into
ethylene glycol ethers and propylene glycol ethers. They are
colorless and almost odorless, and their molecules contain ether
and hydroxyl groups; thus, such ethers behave both as alcohol and
ether and are liquid at room temperature. These ethers can be
further classified into monoethers, which have one of the two
hydroxyl groups substituted, and diethers, which have both the
hydroxyl groups substituted. Monoethers and diethers can be used in
combination of two or more kinds.
[0070] A particularly preferred example of this organic solvent is
a mixture of an alkylene glycol diether, an alkylene glycol
monoether, and a lactone.
[0071] Examples of alkylene glycol monoethers include ethylene
glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene
glycol monoisopropyl ether, ethylene glycol monobutyl ether,
ethylene glycol monohexyl ether, ethylene glycol monophenyl ether,
diethylene glycol monomethyl ether, diethylene glycol monoethyl
ether, diethylene glycol monobutyl ether, diethylene glycol
dimethyl ether, diethylene glycol diethyl ether, triethyelene
glycol monomethyl ether, triethylene glycol monoethyl ether,
triethylene glycol monobutyl ether, tetraethylene glycol monomethyl
ether, tetraethylene glycol monoethyl ether, propylene glycol
monomethyl ether, propylene glycol monoethyl ether, dipropylene
glycol monomethyl ether, dipropylene glycol monoethyl ether, and so
forth.
[0072] Examples of alkylene glycol diethers include ethylene glycol
dimethyl ether, ethylene glycol diethyl ether, ethylene glycol
dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol
diethyl ether, diethylene glycol dibutyl ether, triethylene glycol
dimethyl ether, triethylene glycol diethyl ether, triethylene
glycol dibutyl ether, tetraethylene glycol dimethyl ether,
tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl
ether, propylene glycol dimethyl ether, propylene glycol diethyl
ether, dipropylene glycol dimethyl ether, dipropylene glycol
diethyl ether, and so forth.
[0073] Examples of lactones include .gamma.-butyrolactone,
.delta.-valerolactone, .epsilon.-caprolactone, and so forth.
[0074] Such a preferred configuration would better guarantee the
achievement of objects of the present invention.
[0075] Examples of resins for the glossy ink composition include
acrylic resins, styrene-acrylic resins, rosin-modified resins,
terpene resins, polyester resins, polyamide resins, epoxy resins,
polyvinyl chloride resins, vinyl chloride-vinyl acetate copolymers,
fiber-based resin (e.g., cellulose acetate butyrate and
hydroxypropylcellulose), polyvinyl butyral, polyacrylic polyol,
polyvinyl alcohol, polyurethane, and so forth.
[0076] A non-aqueous emulsion of polymer fine particles (NAD=Non
Aqueous Dispersion) may also be used as the resin. This is a
dispersion that contains fine particles of a polyurethane resin, an
acrylic resin, an acrylic polyol resin, or the like dispersed in an
organic solvent in a stable manner. Examples of those containing a
polyurethane resin include Sanprene IB-501 and Sanprene IB-F370,
manufactured by Sanyo Chemical Industries, Ltd. Examples of those
containing an acrylic polyol resin include N-2043-60MEX and
N-2043-AF-1, manufactured by Harima Chemicals, Inc.
[0077] To further improve the adhesiveness of the pigment to
recording media, such a resin emulsion is added to the glossy ink
composition, preferably at a concentration in the range of 0.1 mass
to 10 mass %, both inclusive. With an excessive amount of the resin
emulsion, the resulting glossy ink composition would lack printing
stability. With an insufficient amount of the resin emulsion, the
resulting glossy ink composition would have an insufficient
adhesiveness.
[0078] The above-described glossy ink composition preferably
contains at least one material selected from glycerin, polyalkylene
glycols, and saccharides. As for the total amount of the
material(s), selected from glycerin, polyalkylene glycols, and
saccharides, they are added preferably at a concentration in the
range of 0.1 mass to 10 mass %, both inclusive.
[0079] Such a preferred configuration would raise the quality of
images on resulting records by preventing the ink from being dried
and thereby preventing clogging while stabilizing the ejection of
the ink.
[0080] Polyalkylene glycols are linear polymers whose backbone is
organized by repeating units linked to each other via ether bonds;
it can be produced by, for example, ring-opening polymerization of
a cyclic ether.
[0081] Specific examples of polyalkylene glycols include polymers
such as polyethylene glycol and polypropylene glycol, ethylene
oxide-propylene oxide copolymers, their derivatives, and so forth.
Any type of copolymer can be used, for example, a random copolymer,
a block copolymer, a graft copolymer, and an alternating
copolymer.
[0082] Preferred specific examples of the polyalkylene glycol
include those expressed by the following formula:
HO--(C.sub.nH.sub.2nO).sub.m--H
[0083] (where n represents an integer of 1 to 5, and m represents
an integer of 1 to 100).
[0084] In this formula, (C.sub.nH.sub.2nO).sub.m may be a single
constant or a combination of two or more numbers as long as the
integer n falls within its specified range. For example, if n is 3,
the formula gives (C.sub.3H.sub.6O).sub.m, and if n is a
combination of 1 and 4, the formula gives
(CH.sub.2O--C.sub.4H.sub.8O).sub.m. Also, the integer m may be a
single constant or a combination of two or more constants within
its specified range. For example, if m is a combination of 20 and
40 in the above-mentioned example, the formula gives
(CH.sub.2O).sub.20--(C.sub.2H.sub.4O).sub.40, and if m is a
combination of 10 and 30, the formula gives
(CH.sub.2O).sub.10--(C.sub.4H.sub.8O).sub.30. Note that every
combination of the integers n and m is allowed as long as the
integers fall within their respective specified ranges.
[0085] Examples of saccharides include monosaccharides such as
pentoses, hexoses, heptoses, and octoses, polysaccharides such as
disaccharides, trisaccharides, and tetrasaccharides, their
derivatives including reduced derivatives such as sugar alcohols
and deoxy acids, oxidized derivatives such as aldonic acids and
uronic acids, and dehydrated derivatives such as glycoseens, amino
acids, thio sugars, and so forth. The term "polysaccharides" refers
to sugars in a broad sense and thus includes common naturally
occurring substances such as alginic acid, dextrin, and
cellulose.
[0086] The above-described glossy ink composition preferably
contains one or more kinds of acetylene glycol surfactants and/or
one or more kinds of silicone surfactants. The surfactant(s) is
added preferably at a concentration in the range of 0.01 mass to 10
mass %, both inclusive, relative to the content of the pigment in
the ink composition.
[0087] Such a preferred configuration would assist the glossy ink
composition in wetting a recording medium, thereby contributing to
rapid adhesion.
[0088] Examples of preferred acetylene glycol surfactants include
Surfynol 465 (trademark) and Surfynol 104 (trademark) (trade names,
manufactured by Air Products and Chemicals, Inc.) and Olfine STG
(trademark) and Olfine E1010 (trademark) (trade names, manufactured
by Nissin Chemical Industry Co., Ltd.).
[0089] The silicone surfactant used is preferably a
polyester-modified silicone or a polyether-modified silicone.
Specific examples include BYK-347, BYK-348, BYK-UV3500, BYK-UV3510,
BYK-UV3530, and BYK-UV3570 (BYK Japan KK).
[0090] The above-described glossy ink composition can be prepared
by a known and commonly used method. An example of applicable
methods is as follows: the above-described metallic pigment, a
dispersant, and the above-described solvent are mixed; a pigment
dispersion is prepared using a ball mill, a bead mill, sonication,
or a jet mill or by some other means; the pigment dispersion
obtained is conditioned to have desired ink properties; then, a
binder resin, the above-described solvent, and other additives
(e.g., a dispersion aid and a viscosity modifier) are added to the
pigment dispersion under stirring, yielding the glossy ink
composition.
[0091] There are some other possible ways to obtaining the glossy
ink composition, for example, a method in which the composite
pigment material is sonicated in a solvent, yielding a composite
pigment dispersion, and this composite pigment dispersion is mixed
with a necessary ink solvent and a method in which the composite
pigment material is put directly into the ink solvent and sonicated
there.
[0092] Although the physical properties of the glossy ink
composition are not particularly limited, for example, the surface
tension is preferably in the range of 20 to 50 mN/m. With a surface
tension of less than 20 mN/m, the ink composition would spread over
the head of the ink jet recording printer used while wetting it or
exude from it, thereby making it difficult to eject ink droplets.
With a surface tension of more than 50 mN/m, the ink composition
would be incapable of spreading over the surface of the recording
medium used while wetting it, thereby making quality printing
impossible in some cases.
[0093] The above-described glossy ink composition may further
contain such additives as contained in ordinary ink compositions.
Examples of applicable additives include, stabilizers (e.g.,
antioxidants or ultraviolet absorbents).
[0094] Examples of applicable antioxidants include BHA
(2,3-butyl-4-oxyanisol) and BHT (2,6-di-t-butyl-p-cresol). Examples
of applicable ultraviolet absorbents include benzophenone compounds
and benzotriazole compounds.
[0095] Next, the black ink composition, which is used in the second
step of the image recording method according to the present
invention, is described.
[0096] This black ink composition is used to form a finishing layer
on a glossy image produced using the above-described glossy ink
composition so that the brightness of the glossy image be reduced.
This finishing layer is obtained by applying a black pigment onto
the glossy image, which has a metallic luster, at a density low
enough to keep the black pigment invisible and is preferably a
layer that decreases the brightness of the glossy image layer
defined as the L* value in the CIE's L*a*b* chromatic system by 0.5
or more.
[0097] This configuration would change the surface properties
(surface uniformity) of the glossy image, thereby further improving
the gloss of the underlying layer, namely, the glossy image
layer.
[0098] The black ink composition used in the present invention is
an ink composition that contains a black pigment. Examples of black
pigments include carbon black (C. Pigment Black 7) such as furnace
black, lamp black, acetylene black, and channel black, metals such
as copper oxide and iron oxide (C. I. Pigment Black 11), and
organic pigments such as aniline black (C. I. Pigment Black 1),
with carbon black preferred for the advantages of the present
invention. These pigments may be used alone or as a mixture of two
or more kinds.
[0099] Specific examples of carbon black includes, but not limited
to, No. 2300, No. 900, HCF88, No. 33, No. 20B, No. 40, No. 45, No.
52, MA7, MA8, MA100, No2200B and other similar products from
Mitsubishi Chemical Corporation, Raven5750, Raven5250, Raven5000,
Raven3500, Raven1255, Raven700, and other similar products from
Columbian Chemicals Company, Regal400R, Regal330R, Regal660R, Mogul
L, Monarch700, Monarch800, Monarch880, Monarch900, Monarch1000,
Monarch1100, Monarch1300, Monarch1400, and other similar products
from Cabot Corporation, Color BlackFW1, Color BlackFW2, Color
BlackFW2V, Color BlackFW18, Color BlackFW200, Color BlackS150,
Color BlackS160, Color BlackS170, Printex 35, Printex U, Printex V,
Printex 140U, Special Black 6, Special Black5, Special Black 4A,
Special Black 4, Special Black250, and other similar products from
Degussa GmbH, and so forth.
[0100] Although not particularly limited, the particle diameter of
carbon black is preferably equal to or smaller than 10 .mu.m, more
preferably, equal to or smaller than 0.1 .mu.m.
[0101] In the ordinary method for recording an image on a recording
medium using a black ink composition, the concentration of the
pigment used is on the order of 2 to 8 mass % so that a black color
can develop. In the present invention, however, the concentration
of the black pigment in the black ink composition is set at 1 mass
or less. When the concentration of the black pigment is equal to or
lower than 1 mass %, the effect of improving the gloss becomes
greater. The concentration is more preferably in the range of 0.1
to 0.5 mass %, in particular, 0.1 to 0.3 mass %.
[0102] Then, the black ink composition used in the present
invention preferably contains a water-soluble resin. The
water-soluble resin contained would improve the closeness of
contact between recording media and glossy images, thereby
improving the resistance of the images to friction. The term
"water-soluble" used herein means that the resin can be dispersed
or dissolved in water or an aqueous medium containing water.
[0103] Examples of applicable water-soluble resins include
water-soluble polymers that have ionic hydrophilic groups derived
from alkali metal salts, ammonium salts, inorganic acid salts,
organic acid salts, and other similar salts of a sulfonic acid
group, a carboxylic acid group, an amino group, or some other
similar group. Specific examples include cellulose derivatives such
as carboxymethyl cellulose salts and viscose, natural polymers such
as alginic acid salts, gelatin, albumin, casein, gum arabic,
tragacanth gum, and lignin sulfonate, starch derivatives such as
cationic starch, starch phosphate, and carboxymethyl starch,
synthetic polymers such as polyacrylic acid salts, polyvinyl
sulfuric acid salts, poly(4-vinylpyridine) salts, polyamides,
polyallylamine salts, condensed naphthalene sulfonic acid salts,
styrene-acrylic acid salt copolymers, styrene-methacrylic acid salt
copolymers, acrylic acid ester-acrylic acid salt copolymers,
acrylic acid ester-methacrylic acid salt copolymers, methacrylic
acid ester-acrylic acid salt copolymers, methacrylic acid
ester-methacrylic acid salt copolymers, styrene-itaconic acid salt
copolymers, itaconic acid ester-itaconic acid salt copolymers,
vinylnaphthalene-acrylic acid salt copolymers,
vinylnaphthalene-methacrylic acid salt copolymers, and
vinylnaphthalene-itaconic acid salt copolymers, and so forth.
[0104] In addition to those listed above, for example, such
water-soluble polyurethane resins as described in Japanese
Unexamined Patent Application Publication No. 2006-342323 may also
be used as the water-soluble resin.
[0105] The water-soluble resin further includes resin emulsions
(polymer fine particles). Examples of applicable resin emulsions
include the polymer fine particles described in Japanese Unexamined
Patent Application Publication No. 2004-225036, which have a
hydrophilic moiety and a hydrophobic moiety; the structure may be a
monolayer structure, a bilayer structure (a core-shell structure),
or any other possible structure. When the polymer fine particles
have a core-shell structure, any structure would be allowed as long
as it contains two or more different kinds of polymers in separate
phases. Examples include a structure in which the shell completely
covers the core, a structure in which the shell partially covers
the core, a structure in which a part of the polymer serving as the
shell forms domains or the like in the polymer serving as the core,
and a multilayer structure organized by three or more layers with
different compositions, in which one or more layers are sandwiched
between the core and the shell.
[0106] From the viewpoint of the above-mentioned resistance to
friction, the concentration of the water-soluble resin in the black
ink composition is preferably at least 20-fold greater than the
concentration of the pigment of the black ink composition on the
solid content basis. More preferably, the above-mentioned ratio of
the water-soluble resin is in the range of 20-fold to 50-fold.
[0107] In addition, the black ink composition may contain such
known additives as described above. Examples of applicable
additives include dispersants, stabilizers, solvents, and so
forth.
[0108] In the image recording method according to the present
invention, an intermediate layer may be formed on the
above-described glossy image layer using a chromatic ink
composition, a white ink composition, a black ink composition, or
the like between the first step for forming the glossy image layer
and the second step for forming the finishing layer unless the
intermediate layer masks the gloss.
[0109] The formation of the glossy image layer, the formation of
the finishing layer, and the formation of the intermediate layer
are preferably based on the ink jet recording method described
later. Also, the finishing layer may partially or completely cover
the gloss image depending on the resulting image desired. From the
viewpoint of improving the closeness of contact between the glossy
image layer and the recording medium used, it is desirable that the
finishing layer cover the entire surface of the glossy image
layer.
[0110] No particular limitation is imposed on the recording medium
used. Examples of recording media used include plain paper, ink jet
paper (matt paper and glossy paper), glass, films made of plastics
such as vinyl chloride, films made by coating a substrate with a
plastic material or an absorbing layer, metals, printed circuit
boards, and many other kinds of recording media.
[Ink Jet Recording Method]
[0111] The ink jet recording method used in the present invention
is a kind of ink jet recording method in which an ink jet head is
driven to eject droplets of ink compositions onto a recording
medium, thereby producing a record, and involves the use of the
above-described ink compositions for image formation.
[0112] Examples of methods for ejecting ink compositions include
the following ones.
[0113] The first method is electrostatic attraction. This method
produces records in any one of the following ways: a strong
electric field is applied between a nozzle and acceleration
electrodes disposed in front of the nozzle, so that ink droplets
are continuously ejected from the nozzle, and then, while printing
information signals are being supplied to deflection electrodes,
the ink droplets travel between the deflection electrodes, yielding
a record; or ink droplets are ejected without being deflected when
the printing information signals control the ejection.
[0114] The second method is a method in which fluid ink is
pressurized using a small pump, and a nozzle is mechanically
oscillated using a quartz oscillator or by some other means, so
that ink droplets are forcedly ejected. The ink droplets ejected
are electrically charged at the same time as the ejection, and
then, while printing information signals are being supplied to
deflection electrodes, the ink droplets travel between the
deflection electrodes, yielding a record.
[0115] The third method is a method involving the use of a
piezoelectric element (a piezo element), in which the piezoelectric
element simultaneously gives pressure and printing information
signals to fluid ink, so that ink droplets are ejected, yielding a
record.
[0116] The fourth method is a method in which thermal energy is
used to make fluid ink rapidly expand. In this method, fluid ink is
heated using microelectrodes, which are under the control of
printing information signals, until it forms bubbles, so that ink
droplets are ejected, yielding a record.
[0117] The above-described methods can all be used for the ink jet
recording method according to this embodiment. From the viewpoint
of high-speed printing, it is preferable that ink compositions be
ejected without being heated. In other words, the first, second,
and third methods of those described above are preferable.
[0118] Incidentally, the ejection rate for the finishing layer,
which contains the black ink composition, is preferably in the
range of 0.1 gram to 20 grams per square meter, more preferably,
0.2 gram to 5 grams per square meter.
[0119] When the above-described recording medium has no
ink-absorbing layer, however, it is preferable that the recording
medium be heated during printing from the viewpoint of speeding up
drying and obtaining better gloss.
[0120] Examples of applicable heating methods include one in which
a heat source heats the recording medium used by coming into
contact with it, ones in which the recording medium used is
irradiated with infrared rays, microwaves (electromagnetic waves
whose wavelength maxima are at around 2,450 MHz), or the like,
blown by hot air, or by some other non-contact means, and so
forth.
[0121] This heating process is preferably performed before printing
and/or at the same time as printing and/or after printing. In other
words, the heating of the above-described recording medium may be
performed before printing, at the same time as printing, or after
printing or even throughout the printing operation. Depending on
the kind of recording medium, the heating temperature is preferably
in the range of 30 to 80.degree. C., more preferably, 40 to
60.degree. C. Heating is not always necessary; just supplying air
using a fan or the like has some effect.
[Records]
[0122] Records according to this embodiment are those recorded
using the image recording method according to the present
invention, preferably, the above-described ink jet recording
method. Such records, obtained using the image recording method
according to the present invention, have an excellent gloss; they
also have an improved closeness of contact with the recording
medium used, thus having an excellent resistance to friction.
[Image Recording System]
[0123] The image recording system according to the present
invention features glossy image formation means for recording a
glossy image layer on a recording medium using a glossy ink
composition containing a metal pigment and finishing layer
formation means for recording a finishing layer on the glossy image
layer using a black ink composition to reduce the brightness of the
glossy image. This image recording system may be a unit that
incorporates the glossy image formation means and the finishing
layer formation means therein or a system that contains both the
means as separate units (e.g., an ink jet recording apparatus is
used for recording, and then another ink jet recording apparatus is
used to form the finishing layer).
EXAMPLES
[0124] Hereinafter, the present invention is further described with
reference to examples thereof; however, it is never limited to
these examples.
(1) Preparation of a Metallic Pigment Dispersion
[0125] A resin-layer coating liquid containing 3.0 mass % of
cellulose acetate butyrate (butylation rate: 35 to 39%;
manufactured by Kanto Chemical Co., Inc.) and 97 mass % of
diethylene glycol diethyl ether (manufactured by Nippon Nyukazai
Co., Ltd.) was uniformly applied by bar coating onto a polyethylene
terephthalate (PET) film with a thickness of 100 .mu.m and was
dried at 60.degree. C. for ten minutes, yielding a thin resin layer
on the PET film.
[0126] Then, an aluminum layer was deposited on the resin layer,
using a vacuum deposition apparatus (VE-1010 vacuum deposition
apparatus; manufactured by Vacuum Device Inc.), to an average
thickness of 20 nm.
[0127] Then, the laminate formed in the above-described way was
subjected to simultaneous delamination, pulverization, and
dispersion in diethylene glycol diethyl ether using an ultrasonic
dispersion apparatus VS-150 (manufactured by AS ONE Corporation)
for a total ultrasonic dispersion time of 12 hours, yielding a
metallic pigment dispersion.
[0128] The metallic pigment dispersion obtained was filtered
through an SUS mesh filter having a mesh size of 5 .mu.m for
removal of coarse particles. Then, the filtrate was poured into a
round-bottom flask, where diethylene glycol diethyl ether was
distilled out using a rotary evaporator; thus, the metallic pigment
dispersion was concentrated. Then, the concentration of the
metallic pigment dispersion was adjusted, so that a metallic
pigment dispersion was obtained with a concentration of 5 mass
%.
[0129] Subsequently, the 50% average particle size R50 based on the
circle-equivalent diameter in the major axis (X direction)-minor
axis (Y direction) plane and the average thickness Z of the
metallic pigment were measured using a particle size/particle
distribution analyzer (FPIA-3000S; manufactured by Sysmex
Corporation); then, R50/Z was calculated from the measurements of
R50 and Z. The result was as follows: The 50% average particle
diameter, R50, was 1.03 .mu.m, the average thickness, Z, was 0.02
.mu.m, and R50/Z was 51.5.
(2) Preparation of a Glossy Ink Composition
[0130] A glossy ink composition was prepared from the metallic
pigment dispersion prepared by the above-described method in
accordance with the composition shown in Table 1. A solvent and
additives were mixed, and the additives were dissolved in the
solvent, yielding an ink solvent, to which the metallic pigment
dispersion was added. Then, the components combined were mixed and
stirred using a magnetic stirrer at room temperature and pressure
for 30 minutes, yielding a glossy ink composition (S1).
[0131] In Table 1, diethylene glycol diethyl ether (DEGDE) and
dipropylene glycol dibutyl ether (DPGBE) were products manufactured
by Nippon Nyukazai Co., Ltd. N-2043-AF-1 (a polyacrylic polyol
resin emulsion) was a product manufactured by Harima Chemicals,
Inc., and BYK-3500 (a surfactant) was a product manufactured by BYK
Japan KK. Note that in this table, the values are expressed in mass
%.
TABLE-US-00001 TABLE 1 Ink composition (glossy ink composition S1)
Concentration (mass %) DEGDE 47.8 DPGBE 45.0 N-2043-AF-1 6.0
BYK-3500 0.2 Inorganic solid matter 1.0
(3) Preparation of a Black Ink Composition
[0132] The ingredients listed in Table 2 below were mixed and then
dispersed with glass beads [diameter=1.7 mm; weighing 1.5-times the
quantity (mass) of the mixture] in a sand mill (manufactured by
Yasukawa Seisakusho) for two hours, yielding a black ink
composition.
TABLE-US-00002 TABLE 2 Ink composition (black ink composition)
Concentration (mass %) Carbon black 0.21 Water-soluble resin 1 0.24
Water-soluble resin 2 5.0 Water-soluble resin 3 20.0 Glycerin 18.0
1,2-Hexanediol 5.0 Triethanolamine 0.9 BYK-348 0.5 EDTA 0.02 Pure
water Balance
[0133] The following lists some of the ingredients contained in the
black ink composition according to Table 2.
[0134] Carbon black: A product from Mitsubishi Chemical
Corporation; trade name: MA8
[0135] Water-soluble resin 1 (a dispersant): A styrene acrylic
resin
[0136] Water-soluble resin 2: A polypropylene emulsion
(manufactured by BYK Japan KK; Trade name: AQUACER593; solid
content: 30 mass %)
[0137] Water-soluble resin 3: Polyurethane (manufactured by Mitsui
Polyurethane, Inc.; Trade name: W6061; solid content: 15 mass
%)
[0138] BYK-348: A polysiloxane surfactant (manufactured by BYK
Japan KK)
(4) Print Evaluation Test
[0139] As a test printer, an ink jet printer PX-5500 (manufactured
by Seiko Epson Corporation) was used. The slot to insert a black
ink cartridge into was filled and mounted with the above-described
glossy ink composition S1, whereas the slot to insert a light-black
ink cartridge into was filled and mounted with the above-described
black ink composition. The recording medium used was photographic
paper (manufactured by Seiko Epson Corporation). The recording
resolution was always set at 1440.times.720 dpi. The recording duty
was set at 100% for the glossy ink composition S1 and 20% for the
black ink composition.
[0140] Here, "duty" is a value calculated from the following
equation:
Duty(%)=Number of dots printed/(Vertical
resolution.times.Horizontal resolution).times.100
[0141] (where the "number of dots printed" is the number of dots
printed per unit area, and "vertical resolution" and "horizontal
resolution" are individually a resolution per unit area. A duty of
100% represents the maximum mass of ink per color for a single
pixel.)
[0142] First, the glossy ink composition S1 was printed on the
recording medium for the evaluation of the resistance to friction
of the glossy image obtained. The result was as follows: The glossy
image did not adhere to the recording medium and was easily removed
upon being touched.
[0143] Then, the brightness (L* value in the CIE's L*a*b* chromatic
system) was evaluated. The L* value in the CIE's L*a*b* chromatic
system was measured using Gretag Macbeth Spetroscan and Spectrolino
(manufactured by X-Rite, Incorporated).
[0144] The result was as follows: the L* value was 40.3 for a print
produced on the recording medium only with the glossy ink
composition S1 and 38.2 for a print produced by further printing
the black ink composition. The L* value in the CIE's L*a*b*
chromatic system for the glossy image dropped when the black ink
composition was printed, and thus the gloss was better on the
glossy image itself than on that covered with a finishing layer,
namely, the black ink composition. Additionally, the closeness of
contact between the glossy image and the recording medium was
confirmed, and the resistance to friction was also confirmed.
* * * * *